Bottle stopper



FIG. 1 is a top, front and left side perspective view of the bottle stopper showing my new design, the broken line showing a bottle is for illustrative purposes only and forms no part of the claimed design;

FIG. 2 is a front elevational view thereof, the rear elevational view being the same;

FIG. 3 is a left side elevational view thereof, the right side being the same;

FIG. 4 is a top plan view thereof; and,

FIG. 5 is a bottom plan view thereof, the broken lines forming no part of the claimed design. 

The ornamental design for a bottle stopper, as shown and described. 